It is common to provide a graphical user interface for user interaction with computer systems. Such an interface provides to the user presentation of information about the computer and its components and associated systems and data, both hardware and software. By use of graphical objects such as windows, icons, toolbars, control boxes and control buttons, the user is shown what software modules are available for selection and execution. One common aspect of computer interfaces is the directory tree structure, which provides a structure for organising information (e.g. software applications or computer files) which have related subject matter or common themes as nodes or limbs of a directory tree. The information is thus organised into a set of directories and sub-directories. This powerful tool provides an intuitive representation of logical groupings and relationships between such logical groupings of multiple pieces of information. Within the directory tree structure, a user can select and manipulate pieces of information (e.g. files, or weblinks) represented by nodes or limbs within the tree using a mouse, keyboard, trackball, pointer, remote control cursor or other user-operated input device. User selection via a mouse can be accomplished by ‘pointing and clicking’ on a selectable feature on the computer display.
While the directory tree structure is very useful, it is not the best solution for many applications. Interfaces for consumer home use, such as navigation interfaces for interactive media players, should ideally be wholly user friendly and intuitive, as users of such systems may have a very limited knowledge and understanding of computer operation. In addition, such interfaces should be fully visual, constantly providing as much relevant graphical information to the user as possible, without requiring any complex navigation or user selection strategy. In this regard conventional directory tree structures are far from ideal, as they generally require controls which allow a given subdirectory to be expanded into view, or conversely to be hidden or collapsed from view, and this requires careful selective navigation by the user. In addition, the usual approach necessitates careful manipulation by the user to scroll through items of a selected subdirectory. Further, in the conventional directory tree approach, all items within a particular target subdirectory are displayed with equal emphasis, even though the majority may be irrelevant to a current task or content sought.